Arc chute



March 11, 1947.

W. M. SCOTT, JR

ARC CHUTE Filed Jan. 12, 1945v 2 Sheets-Sheet 1 @MA ATMRNEY.

March 1l, 1947. w, M, SCOTT, JR 2,417,134

ARC CHUTE Filed Jan. 1.2, 1945 2 Sheets-Sheet 2 INVENToR. if M. fcorrJR.

/nm um A TToRNEY.

Patented Mar. 11, 1947 UNITED STATES PATENT OFFICE ARC CHUTE ApplicationJanuary 12, 1945, Serial No. 572,553

4 Claims.

My present invention relates to circuit inter rupters and moreparticularly to a novel arc quencher therefor comprising a plurality ofspaced plates of insulating material arranged above and parallel to thearc, the said plates being intersected by a number of transversemetallic rods.

More speciically, my invention relates to a novel and simplied blow-outmeans readily adapted to be used in connection with the said metallicrods and which requires a minimum of additional parts and virtually nomaintenance and repair.

This application embodies some of the principles of my applicationSerial No. 550,179, led August 19, i944, and embodies substantially thedisclosure therein set forth together with the additional simple andnovel blow-out mechanism.

Essentially, my invention contemplates that the upper transversemetallic rods have an iron core in order to provide a magnetic blow-out.These upper transverse rods may also extend through a pair of ferrousside plates in order to enhance the blow-out effect.

in the construction and operation of circuit interrupters, it isfrequently necessary to provide means for extinguishing quickly the arcwhich is drawn between the contacts as they separate. Such circuitinterrupters, which may be tripped open on the incidence of highcurrents, comprise a pair of main contacts (to carry the full currentduring normal'operation), which are arranged to make after and breakbefore a pair of parallel -arcing contacts so that any arcing which mayoccur will not pit or otherwise destroy the contact surfaces of the maincontacts.

slots are well known.

My invention contemplates as its essential function the provision of anarcv chute which utilizes both the principle of spaced insulating'plates tc lengthen and squeeze the arc, together with a series ofmetallic surfaces with'which the arc is brought into contact and brokenup into a series of small arcs and cooled.

More specifically, my invention contemplates a plurality ofV spacedinsulating plates'extending (Cl. 20G-447) 2 in a direction parallel t0the path of the arc into which the arc is forced by blow-out means, thesaid spaced insulating plates being used in combination with a series oftransverse metallic members which will break the arc into a plurality ofarcs in series and will also further cool the same.

Still more speciiically, my invention contemplates that these metallicsurfaces be formed by a series of transverse pins, each of which extendsthrough all of the insulating plates and each of which furnishes aconductive path between the various slots defined by the spacedinsulating plates.

The primary object of the present invention is the provision ofsimplified blow-out means which comprises making a substantial portionof the transverse metallic rods or pins of the arc chute of a suitableconductive material, such as copper, but making the upper row or rows oftransverse pins of iron in order to provide a suitable magnsti@blow-out. These upper iron transverse pins may have a sleeve or coatingof copper in order that these upper pins may also act as arcextinguishing pins.

Another object of my invention is the arrangement of the upper ironcopper coated transverse rods or pins so that they may cooperate with orform a part of other blow-out means such as a pair of ferrous sideplates.

These and many other objects of my invention will become apparent in thefollowing description and drawings in which:

Figure l is anend View taken from line l--I of Figure 2 of my novel arcextinguisher.

Figure 2 is a view partly in cross section taken from line 2-2 of Figurel looking in the direction of the arrows and showing the compound uppertwo rows of transverse pins which have an iron core and copper coatingor sleeve.

Figure 3 is a front View of a slightly modiiied form of arc extinguisherin which the construction of the upper two rows of compound pins isslightly varied so that these pins may coop- 'crate with a pair offerrous Side plates.

Figure 4 is a side view of the arc chute of Figure 3 showing one of theferrous side plates.

Figure 5 is a longitudinal cross sectional view taken on line 5-5 ofFigure 3 showing the construction ci the compound copper-iron blowoutpin.

Figure 6 is a cross sectionalview taken on line -i of Figure 5 furthershowing the construction of the compound copper-iron pin of the arcchutes of Figures 3 and 4.

Referring now to Figures 1 and 2, I have here shown an arc chutecorresponding in every respect to the arc chute disclosed in myapplication Serial No. 550,179, except that the magnetic blow-out coilin series with the arcing horn is no longer used, but instead the uppertwo rows of pins in the embodiment shown have iron cores and coppercoatings or sleeves.

The arc quencher 2b also has the construction and operation generallyshown in my Patent No. 2,348,228. The arc chute 2li comprises a pair ofside supporting plates 2l, 2l of insulating material, between which aremounted a number of spaced arc extinguishing plates 23, 2li, 25, 2li,2l, also of insulating material. The plates are integrated as a singleunit by the transverse bolts itil, SI, 32, 33, which are provided withinsulated bushings 35, 35.

Bolts 3E and 3l are also provided with indiw vidual insulating washersor spacers 3l', 3l to maintain the spacing between the irrsulatingplates at the iront of the arc quencher. Bolts 32 and 33 carry a set ofinsulating spacers S3 between each pair of plates which serve to spacethe back ends of the plates from each other; the said spacers 38 alsoeach having a hook-shaped extension 39 to engage a hook 4t on the upperend of the arcing horn di, which is secured to the back panel 42 onwhich the circuit breaker is mounted. The plates 23-21 are accordinglyinsulated from each other and from the side plates 2|.

The side plates 2l, 2l also carry between them on the transverse boltsill and l5 the opposite arcing horn llt. The said arcing horn i6 anextension :lll carrying a bolt i8 which may be secured tothe stationaryflange member i9 carried by the transverse insulating bridging support5B in order to secure the arc chute in position. A conductive connectionis made to the arcing horn i5 through the flange member le and thepigtail 52.

The arc quencher 2i) is particularly characterized by a large number oftransverse copper pins B, il@ which pass through perforations in theplates 23, 2li, 25, 26, 2l, as shown in Figures l and 2, and which aresupported thereby. The pins Si? preferably do not contact the oppositesupporting insulating members 2i, 2i. This will facilitate assembly andadjustment of the unit, permits the pins to be brought down close to thecontacts which form the arc, removes the possibility of breakdown orcreepage along the supporting plates 2l, 2l. IThe remainder of thestructure shown corresponds to the circuit break er shown in my PatentNo. 2,348,228.

Essentially, the circuit breaker here shown comprises a lower backconnection stud (not shown) to which the main movable contact 'l2 (onthe contact arm 65) the arcing horn ll8lll,

-and the. arcing contact i8 are connected respectively by a pigtail (notshown), pigtail 52, and pigtail 66. The circuit breaker also cornprisesan upper back connection stud lil to which is secured the mainstationary contact l l, which engages the main movable contact 'l2mounted on the contact arm 65 to complete a circuit from the upper tothe lower connection studs. And also mounted on the back connection stud'lil is the connecting bracket 'i3 which is connected to the stationaryarcing horn il at the end of which the stationary arcing contact 'il iscarried.

When the main contacts 'il and l2 have separated, while the arcingcontacts hereinafter described are engaged, current flows from the backconnection stud l@ through the connecting blown upwardly thereon.

bracket 13 and the lower end of the arcing horn 4i, to the stationaryarcing contact l?, then to the movable arcing contact 'iii mounted onthe Contact arm 65, and then through the pigtail 66 to the lower backconnection stud.

is arcing contacts il and it separate, an arc is drawn therebetween. Asthe opening move ment is completed, the root of the arc at contact TE isblown upwardly along the arcing horn lll while the root of the arc atmovable arcing contact i8 is transferred to arcng horn 43 and Theblow-out means, hereinafter more specically described, blows the centerof the arc upwardly into the center ol the plates 23 to 2i. I"ihe platesto 2l are longest in a vertical direction at plates 23 and 2l; that is,the downwardly extending cusps 2li thereof extend further downwardly inthe case of theseplates. The center plate 25 has the shortest cusp $2.The intermediate plates 2.4i and 26 have cusps ill of intermediatelength, as shown more particularly in Figure 2 and in dotted lines inFigure 1.

Thus, in a transverse direction, the plates of the arc chute present aV-shape which tends to guide the arc toward the center of the chute. Thedownwardly extending cusps 80, 8l and 82 intercept the center of the arcand tend to guide the arc in its upward movement to squeeze into theconiined space between the plates.

The arc in being driven upwardly tends to be squeezed into but one ofthe spaces, for instance, in the space between plates 24 and 25 or inthe space 85 between plates 25 and 26. It is not necessarily conned toeither or both of these spaces but may be broken up into a plurality ofparallel arcs in separate spaces.

While this type oi" arc chute having only the spaced insulating plates23 to 2l has been eiective in use, it has been found that perhaps onlyone or two of the spaces, and usually only one, are actually effectivein extinguishing the arc. That is, the arc is forced up into but one ofthe four spaces which it may normally enter, is squeezed between thesurfaces of the plates defining the space, and is extinguished therein.

The arc, in addition to being initially compressed in one or two of theslots or spaces between the plates, is intercepted transversely by theplurality of metallic surfaces which dene the pins 69. I'hese pins B0,which are of highly conductive material, preferably copper, tend tobreak the arc up in series among them. That is, should the arc besqueezed, say, into the slot 85, it will encounter a number of pins 60,as shown by the dotted line 9i), and will be broken up into a series ofsmall arcs between these pins.

In addition, as the arc is driven upwardly, the initia1 small seriesarcs will go out and new arcs, as indicated at Si, will beestablishedacross other pins, which eiect a new cooling action on thearc. As the arc moves still further upwardly, it will encounter stillmore pins and be broken up into a larger number of small arcs in series.This continuous tearing of the roots of the small arcs from the lowerpins and reestablishing the small arcs above the small arcs which havebeen extinguished, will render the arcs unstable and lead to quickextinguishment.

The surfaces of the pins 52 will tend further to cool the arc while thearc roots move along from pin to pin, and will result in quickextinguishment of the arc. Not only does this action take place withinthe vprincipal slot (for instance, 85) into which the arc is rstsqueezed, butl by vand arc extinguishing means within the arc chute;said means for moving the arc inte the chute comprising a plurality offerrous pins eX- `tending transverse to the arc path substantiallyremote from the point of entry of the arc into the arc chute; a pair offerrous plates on either side of the arc chute enacting with saidtransverse ferrous pins to forni a U-shaped magnetic path; a pluralityof insulating plates extending in planes parallel to the path of theare, said insulating plates supporting said transverse ferrous pins inspaced relation to each other.

2. An arc chute comprising means for drawing an arc; means for movin theare into the chute;

and arc extinguishing means within the arc chute; said means for movingthe arc into the chute comprising a plurality of ferrous pins extendingtransverse to the arc path substantially remote from the point of entryof the are into the arc chute; a pair of ferrous plates on either sideof the arc chute coacting with said transverse ferrous pins to forni aU-shaped magnetic path; said are chute having a pair of insulating sidewalls arranged parallel to the path of the arc; said transverse ferrouspins extending through and being supported by insulating side Walls;said ferrous plates being supported by said insulating side Walls; theends of said transverse ferrous pins engaging said ferrous plates.

3. An arc chute comprising means for drawing an arc; means for movingthe arc into the chute; and are extinguishing means Within the arcchute; said means for moving the arc into the chute comprising aplurality of ferrous pins extending transverse to the arc pathsubstantially remote from the point of entry of the arc into the arcchute; a pair of ferrous plates n either side of the arc chute coactingWith said transverse ferrous pins to form a U-shaped magnetic path; saidarc chute having a pair of insulating Aside Walls arranged parallel tothe path of the arc; said transverse ferrous pins extending through andbeing supported by said insulating side walls; said ferrous plates beingsupported by said insulating side walls; the ends of said transverseferrous pins engaging said ferrous plates; said ferrous pins Jhaving aninsulating sleeve extending along the length thereof at least up to theinterior surfaces of said insulating side Walls.

4. An arc chute comprising means for drawing an arc; means for movingthe arc into the chute; and arc extinguishing means within the arcchute; said means for moving the arc into the chute comprising aplurality of ferrous pins extending transverse to the arc pathsubstantially remote from the point of entry of the arc into the arcchute; a pair of ferrous plates on either side of the arc chute coactingwith said transverse ferrous pins to form a ill-shaped magnetic path;said arc chute having a pair of insulating side Walls arranged parallelto the path of the arc; said transverse ferrous pins extending throughand being supported by said insulating side walls; said ferrous platesbeing supported by said insulating side Walls; the ends of saidtransverse ferrous pins engaging said ferrous plates; said ferrous pinshaving an insulating sleeve extending along the length thereof at leastup to the interior surfaces of said insulating side Walls; and aconductive metallic coating over said insulating sleeve.

WILLIAM lVI. SCOTT, JR.

REFERENCES CITED The following referencesare of record in the lle ofthis patent:

UNITED STATES PATENTS Number Name Date 900,798 Corey Oct. 13, 19081,519,230 Aalborg Dec. 16, 1924 2,133,158 Ver Planck et al. Oct. 11,1938 2,180,147 Hopp Nov. 14, 1939

